DE3122342A1 - FINE-PART EXPANDABLE STYRENE POLYMERISATES - Google Patents

Abstract

Fire retardant, expanded styrene polymer shaped objects are prepared by: (a) mixing styrene monomer or a mixture thereof with at least one comonomer, an expanding agent and a fire retardant, organic halogen compound in a aqueous dispersion; (b) adding to (a) either before or during polymerization from about 0.0001 to 0.1 percent by weight esters soluble in the organic phase of (a), these esters of aliphatic dicarboxylic acids and aliphatic epoxy alcohols having at least 11 carbon atoms; (c) polymerizing the aqueous dispersion of (a) and (b) using radical forming initiators at a temperature of about 80 DEG to 130 DEG C.; (d) separating bead polymers having diameters between about 0.4 and 3 mm; (e) pre-foaming the beads; (f) ageing the pre-foamed beads; and (g) final forming the aged and pre-foamed beads in a pressure resistant mold.

Description

Foam bodies are made in technology by expanding finely divided, expandable styrene polymers in molds •manufactured. In this process, the finely divided styrene polymers are first heated with steam or hot Gases are heated to temperatures above their softening point, causing foaming into discrete particles entry. This process, in which the particles have enough space for free expansion, is called Prefoaming. The pre-expanded styrene polymers are first deposited and then in a pressure-resistant, however non-gas-tight form by reheating with steam further expands, whereby, due to the space limitation, the particles together to form one of the inner cavity Weld the molded body corresponding to the shape used. This second step is called foaming designated. The molded body can only be removed from the mold without deformation if it is also inside Temperatures below the softening point has cooled. One describes the period of time after which one at the earliest can remove a molded body from the mold without it expanding, usually as a minimum mold dwell time. as The breakdown of the Serve internal pressure to almost atmospheric pressure. The molded body is usually still after it has been removed from the mold stored for some time until completely cool and can then be turned into foam sheets for thermal insulation purposes get cut.

In the production of the expandable styrene polymers, especially when a flame-retardant organic Halogen compound was added, products with irregular cell structure. Such foam blocks tend not just some time after demolding to the stronger one

Their side surfaces collapse (block shrinkage), but are also less welded inside the block. Through this the foam sheets cut from a block have different qualities. In addition, the blocks that have failed on the side surfaces are trimmed,. creating unwanted waste.

Another problem arises with prefoaming, since part of the prefoaming beads shrinks, thereby making desired low densities cannot be set. The shrinkage of the pre-expanded beads is at a high loss connected to propellant, what the above-mentioned unequal- ' moderate welding and thus the collapse of the blocks on the string surfaces promotes. In addition, the The surface of the finished parts has an uneven appearance, which is particularly annoying in the production of face plates.

From DE-AS 21 04 867 it is known that the addition of Hydroxylamines to expandable styrene polymers, the are self-extinguishing by organic halogen compounds, the processing problems mentioned above be improved. DE-AS 25 20 635 describes a similar effect by adding small amounts of Amines free of hydroxyl groups and in DE-OS 28 07 710 are triazine derivatives substituted with amines for the remedy the known processing problems claimed.

In some cases, all of these additives bring about a significant improvement in the product properties. It will be ^ which, however, are not yet fully satisfactory products, obtain. Above all, the poor reproducibility of the product properties is a problem.

The object of the invention was to find compounds which occur even in low concentrations of the defects mentioned above, such as irregular

° · ^ζ · 3734

Prevent cellularity, welding and block shrinkage. In addition, these additives should be replaced by the polymerization auxiliaries required for production, such as Initiators, suspension auxiliaries or other additives, such as flame retardants, propellants in their effect are not impaired, so that the> achieved product quality can be adjusted reproducibly.

It has now been found that in the to be polymerized Monomeric soluble esters of aliphatic dicarboxylic acids with aliphatic epoxy alcohols, their total carbon number has at least 11 carbon atoms, the important processing properties "weld quality" and "Blockschr- ^ r.pf" of foam blocks made of expandable, Styrene polymers containing organic halogen compounds favorably influence and those with the Amxnzusatz do not have the described disadvantages. The styrene polymers obtained according to the invention have a higher processing latitude, i. H. at different vapor pressures when foaming in the Form, foam blocks with good welding and excellent surface properties are always obtained.

For the purposes of the invention, epoxy esters are the bis-glycidyl esters of glutaric acid, adipic acid, pimelic acid, suberic acid and azelaic acid as well as the sebacic acid of dodec- • candioic acid and brassylic acid, in particular bis-glycidyl dodecanedioate. Because of their better solubility in styrene, branched-chain bis-glycidyl esters of dicarboxylic acids, such as B. 2,2,4-trimethyladipic acid is preferred.

The production of the epoxidation products, for which no contactor is sought in the context of this invention, takes place according to known methods, e.g. B. through implementation

O.Z. 3734

- @ ofe§spinscifeejaänen acid salts with epichlorohydrin (R.

Mii1sh ©; that of organic chemistry (Houben Weyl) 549 (1963).

pens ion sh i 1 f srui.

S ÜSs®g§4gn§ifs process for the production of the invention, an organic halogen compound as well as a yield with / ltinth-containing styrene polymer takes place in to §ich.ib.g & annter way through the polymerization of styrene

usual comonomers in aqueous

1 © & * §g§n§ign ^ by means of radical-forming initiators at Tem- §ilSSQtKSiR ₄ , over 80 C in the presence of flame retardant

^unc ^ blowing agents, the epoxidation product soluble in the organic being added to the hydrocarbons during the polymerization.

of the claimed epoxies seems | Solubility in the organic phase of the good solubility of the added organic j (flame retardants) in the epoxy j to play. j

They will look for "." - "

Epoxies are used in amounts of 0.0001 | but from 0.001 to 0.1 weight j v ^ Oj & ejfc-fe ^ t ^ ezMsiien on the monomers to be polymerized, '

.: in each case the amount to be used is i Amount of organic halogen gel added. One can either add the substances to the pjljase or the reaction mixture before or

Add the end of the polymerization, with epoxides during the polymerization

50 to 90% possibly together with the “is preferred. The amount of epoxy or the

The addition is independent of the temperature control of the polymerization or independent of the type of the initiator used. The amount and type of

- 6 - O.Z. 3734

Epoxides, however, depend on the type of halogen compound incorporated, which is easy to establish experimentally _; averaging is.

Starting materials in the production of the 'according to the invention

Styrene polymers are monomer mixtures that contain at least '

50 percent by weight styrene and possibly as a mixed polymer ^!

tion components z. B. Qf- methyl styrene, halogenated in the nucleus ^! Styrenes, acrylonitrile, esters of acrylic and methacrylic acid

of alcohols with 1 to 8 carbon atoms, N-vinylver- j

bonds, such as N-vinylcarbazole or small amounts]

Contain butadiene or divinylbenzene. !

The polymerization is expediently carried out by the bead polymerization process known per se at temperatures from 80 to 130.degree. She will do it in the usual way
initiated with one or more radical-forming substances J, t-butyl perbenzoate, t-butyl peroctoate, j di.-t-butyl peroxide, dibenzoyl peroxide or mixtures thereof being mentioned as examples. j

As organic halogen compounds are in particular
Bromine compounds, such as the brominated oligomers of the
Butadiene or isoprene with a medium poly-

5 degree of merization from 2 to 20 used, the bromination being complete or partial: 1,2,5,6-tetrabromocyclooctane, 1,2,5,6,9,10-hexabromocyclododecane,
brominated polybutadiene with a degree of polymerization
from Z. B. 3 to 15. The organic halogen compounds

can be used in amounts of 0.05 to 1 percent by weight
Use as a flame retardant in quantities of 0.4 to 3
Be contained in percent by weight in the expandable styrene polymer. In addition to halogen compounds as
Flame retardants can use the known synergists in

customary amounts are used, preferably organic peroxides, in particular those with a half-life
of at least two hours hai 373 K.

O.Z. 3734

Organic protective, colloidal, such as polyvinyl alcohol, polyvinylpyrrolidone or polyvinylpyrrolidone copolymers or mineral suspension aids, such as finely divided tricalcium phosphate, barium phosphate, etc. can be used.

As a blowing agent for the inventive method, for. B. aliphatic hydrocarbons such as propane, butane, Pentane, hexane, cycloaliphatic hydrocarbons, such as cyclohexane, or halogenated hydrocarbons, such as dichloro j di fluorine than, l, 2,2-trifluoro-l, l, 2-trichloroethane a | set. Mixtures of these compounds can also be used be turned. The amount of propellant is from 3 to 15 percent by weight, preferably between 5 and 8 percent by weight based on the styrene polymer. ,

The expandable styrene polymers can also contain additives such as dyes, fillers and stabilizers. After production, they are in finely divided form (e.g. pearl form) and generally have a particle diameter of 0.4 to 3 mm. i They are foamed in a pre-expanded state in the usual way by heating them in molds that do not close gas-tight, then further foamed and sintered to form foam bodies, the dimensions of which correspond to the inner cavity of the molds used. The styrene polymers according to the invention can be processed into extremely dimensionally stable moldings. Foam blocks measuring 1 χ 1 χ 0.5 ra have only a very slight tendency to collapse of the side surfaces after demoulding.

The foam bodies or blocks are also characterized by particularly good welding of the individual particles . They therefore have particularly good mechanical stability.

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Examples

A mixture of 100 parts by weight was placed in a pressure-resistant stirred tank made of corrosion-free steel deionized water, 100 parts by weight of styrene, 0.4 parts by weight of benzoyl peroxide, 0.1 part by weight of tert-butyl perbenzoate, 0.75 parts by weight of hexabromocyclododecane, 0.30 parts by weight of dicumyl peroxide and those in the

of the corresponding epoxy ester Table 1 indicated amount äsrxe "■ -

(dissolved in styrene) heated to 90 ° C. with stirring. After 2 hours at 90 ° C, 5 parts of a 2% aqueous Solution of polyvinyl alcohol with a saponification number of 140 was added. After a further 2 hours the: Addition of 7 parts by weight of a mixture of 25 percent by weight iso- and 75 percent by weight of n-pentane inside half from 10 to 15 minutes. The approach was heated to 120 ° C. for a further hour at 90 ° C. and held at this temperature for 6 hours.

After the end of the polymerization cycle, the mixture was cooled and the bead polymer formed was removed from the aqueous Phase separated, dried and sieved.

The pearl fraction between 1 and 2 mm in diameter was processed in a continuous Rauscher type pre-foamer Pre-foamed with flowing steam to a bulk density of 15 g / l, temporarily stored for 24 hours and then in a block form with the dimensions 100 χ 50 χ 100 cm type Rauscher with different steam pressures foamed into foam blocks. The test values are compiled in Table 1. Every example was repeated at least 5 times. In addition to the test values, the standard deviations are given, which are at the comparative examples are clearly higher than in the inventive examples.

Tabel,. 1

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O.Z. 3734

Table 1 - Port setting

2. Comparative examples

additive additive
lot
Weight ~% Bulk weight
increase
g / l ¹ ' Steam.
Time
sec. ²⁾ steam
pressure
bar ³⁾ Conspiracy-
Degree t
t ³ P
40 block
shrink +
+ 0.5
0.5 block
upper fl. ⁶⁾ Cell structure.
Cells / mm until
until 10
10 Ν, Ν-dicyclo-
hexylamine 0.005 0.5 + 0.2 20th
20th 1.8
1.5 70
60 +
+ 40
20th 0.5
0.7 +
+ 0.7
0.6 Well
Well 2
2 until
until 10
10 N-tetradecyl
amine 005 0.4 + 0.2 20th
20th 1.8
1.5 60
70 +
+ 40
30th 0.8
0.6 +
+ 0.5
0.6 Well
Well 2
2 until
until 20th
20th 2,4-diamino
6-nonyl-l, 3.5-
triazine 005 0.8 + 0.4 20th
20th 1.8
1.5 60
70 +
+ 40
40 1.0
1.2 +
i 0.5
0.5 Well
Well 10
10 until
until 10
10 Bis- (hydroxi-
ethy]) - dodecyl-
amine 0.05 1.0 + 0.5 20th
20th 1.8
1.5 60
60 1.5
1.3 Well
Well 2
2

- JLe <- O.Z. 3734

- A4-

Table 1 - continued

Increase in bulk density of the pre-expanded beads pneumatic conveying in a silo and 24 hour intermediate storage.

The time from when the is reached counts as the steaming time specified steam pressure in the block form until the steam supply valve is closed »

10.

3)

Steam pressure in the block form.

4)

The degree of welding is the ratio of the number of particles torn through to the total number of particles χ 100 (= percent) understood. A foam sheet measuring 100 χ 100 x serves as the test object 5 cm.

Block shrinkage is understood as the collapse of the side surfaces, which occurs 24 hours after the Block is measured. Block shrinkage is determined by taking the block density from the center of a large side surface to the opposite at right angles to these side surfaces. The difference the clear dimensions at this point and the block thickness Converted at this point as a percentage of the clear dimensions results in block shrinkage.

'The block surface is said to be good if there are no sunken, molten-looking pearls can be observed on it.

'For the microscopic determination of the cell number were

Plates removed from the block at different locations per experiment and counted. The stated values are the highest and lowest determined cell numbers. The closer the values are to each other, the more homogeneous the cell structure of the block is.

Claims (1)

O.Z. 3734 Ideas iJaee-- - - Patent claims: sis ä also in B. i \ Fein € e \ fge, expandable styrene polymers, a P ^ räibmri ^ e'l and a flame-retardant organic halogen ^on vlrbiMlnf containing, that in addition 0.0001 to 0.1 percent by weight, based Another one. ρ,. . . . on the styrene polymer, xn the polymerxsxerenden J fl "" ■ ^ Mondmeren'MÖsliche esters of aliphatic dicarbon ^na * ^e iää? In ^I? Ä ^ ^t contain aliphatic epoxy alcohols, Seligöggl || § _a ^ _t carbon number increases at least 11 carbon atoms. ψ} SIpanSiirSIre styrene polymers according to claim 1, ϊ "5 ^υ ' ^ν ®1ΙαδχΊ2ίΙ f! indicates, epoxidation product soluble in the monomers in amounts of 0.001 to 0.05 percent by weight, based is included. ^ Sllr manufacture of hard-to-deflate, ex- Αϊ ,? s ^ VCs f "'(i" S ci ¹ ^ "* / ^ i'C- ³ c *> * ΰ" » "" panaierüar * eh styrene polymers through Polymerxsatxon ^vföi vo ^ ^s l € ya? ol ^r and possibly customary comonomers in ^ah " ^ä waBrxge ^: r ^Ci iu ⁴ s'pension in the presence of flame-retardant ^iiyö 'o? gliw.s ^l cSen ^{r £} Halogen compounds by means of radical- ^{forming wsrc} dlr ^ iifiWoren at elevated temperatures with addition characterized, · or during the polymerization from 0.0001 to ozent, based on the polymerize- ^{> J} 30 ^aeß iei ^^ SndnfeiFön, in the organic phase of the suspension ^te l ^ s ^ feifk is% he of aliphatic dicarboxylic acids with ^ e ^^^^^ jp ^^ Vgyj adds epoxy alcohols, their Total carbon number at least Ii carbon atoms grows. find “ the sclio join the obfex.